Prognostic models of development of processes of catastrophic long-term annual river runoff formation

2010 ◽  
Vol 35 (10) ◽  
pp. 695-699
Author(s):  
V. V. Kovalenko ◽  
E. V. Gaidukova ◽  
D. V. Chistyakov ◽  
A. Hamlili
Keyword(s):  
River Runoff ◽  
Prognostic Models ◽  
Runoff Formation ◽  
Models Of Development

scholarly journals Results of probabilistic hydrological processes research at RSHU

2020 ◽  
pp. 255-268
Author(s):  
V.V. Kovalenko ◽  
E.V. Gaidukova ◽  
N.V. Viсtorova ◽  
V.A. Khaustov ◽  
V.S. Devyatov
Keyword(s):  
River Runoff ◽  
Anthropogenic Activity ◽  
Runoff Formation ◽  
Runoff Series ◽  
Catchment Areas ◽  
The Future ◽  
Climatic Scenarios ◽  
Forecast Models ◽  
Engineering Hydrology

Currently, long-term estimates can be obtained either under the assumption of statistical stationarity of hydrometeorological processes using actual series of observations for the previous decades, i.e., in fact, by extrapolating “frozen” current probabilistic estimates to the future, or by modeling (calculation) based on equilibrium climatic scenarios under the assumption of statistical sustainability of runoff series, according to which parameterization of forecast models of runoff formation is conducted. The article considers the methodology of partially infinite hydrology, which includes sustainable forecasting of runoff and diagnostics of bifurcations of its formation, allows solving fundamentally new hydrological problems (including problems of engineering hydrology) related to the possibility of obtaining longterm estimates of probabilistic characteristics of long-term river runoff under the conditions of evolutionary changes in the runoff formation factors (climate and anthropogenic activity in catchment areas). Using the methods and patterns of partially infinite hydrology and relying only on the available hydrometeorological information (obtained at the state network of standard observations), known climatic scenarios and plans for the socio-economic development of the territory, the following main results have been obtained: 1) river basins have been diagnosed (as well as time intervals in the future), the ones in which (and when) it is possible to change the additive mechanism of the smooth evolution of the flow formation process to a bifurcation mechanism (the appearance of bifurcation foci) being identified, i.e. engineering hydrology documents can be questioned; 2) a methodology has been developed for sustainable forecasting of the probabilistic characteristics of long-term river runoff using various options for its formation models (unimodal, polymodal, one-dimensional, multidimensional, etc.).

scholarly journals Zonal aspects of the influence of forest cover change on runoff in northern river basins of Central Siberia

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
A. Onuchin ◽  
Т. Burenina ◽  
А. Shvidenko ◽  
D. Prysov ◽  
A. Musokhranova
Keyword(s):  
River Runoff ◽  
Catchment Area ◽  
Forest Cover ◽  
River Basins ◽  
Forest Vegetation ◽  
Middle Taiga ◽  
Northern Eurasia ◽  
Runoff Formation ◽  
Forest Tundra

Abstract Background Assessment of the reasons for the ambiguous influence of forests on the structure of the water balance is the subject of heated debate among forest hydrologists. Influencing the components of total evaporation, forest vegetation makes a significant contribution to the process of runoff formation, but this process has specific features in different geographical zones. The issues of the influence of forest vegetation on river runoff in the zonal aspect have not been sufficiently studied. Results Based on the analysis of the dependence of river runoff on forest cover, using the example of nine catchments located in the forest-tundra, northern and middle taiga of Northern Eurasia, it is shown that the share of forest cover in the total catchment area (percentage of forest cover, FCP) has different effects on runoff formation. Numerical experiments with the developed empirical models have shown that an increase in forest cover in the catchment area in northern latitudes contributes to an increase in runoff, while in the southern direction (in the middle taiga) extensive woody cover of catchments “works” to reduce runoff. The effectiveness of geographical zonality in regards to the influence of forests on runoff is more pronounced in the forest-tundra zone than in the zones of northern and middle taiga. Conclusion The study of this problem allowed us to analyze various aspects of the hydrological role of forests, and to show that forest ecosystems, depending on environmental conditions and the spatial distribution of forest cover, can transform water regimes in different ways. Despite the fact that the process of river runoff formation is controlled by many factors, such as temperature conditions, precipitation regime, geomorphology and the presence of permafrost, the models obtained allow us to reveal general trends in the dependence of the annual river runoff on the percentage of forest cover, at the level of catchments. The results obtained are consistent with the concept of geographic determinism, which explains the contradictions that exist in assessing the hydrological role of forests in various geographical and climatic conditions. The results of the study may serve as the basis for regulation of the forest cover of northern Eurasian river basins in order to obtain the desired hydrological effect depending on environmental and economic conditions.

ESTIMATION OF LONG-TERM CHANGES IN QUALITATIVE CHARACTERISTICS OF THE OKA RIVER RUNOFF

2021 ◽  
pp. 98-104
Author(s):  
G. KH. ISMAIYLOV ◽  
◽  
N. V. MURASCHENKOVA ◽  
I. G. ISMAIYLOVA
Keyword(s):  
River Runoff ◽  
Maximum Concentration ◽  
Temporal Dynamics ◽  
Ammonium Nitrogen ◽  
Oil Products ◽  
Copper Compounds ◽  
Long Term Changes ◽  
The City ◽  
Qualitative Characteristics

The results of the analysis and assessment of long-term changes in the qualitative characteristics of the Oka River runoff are presented. To analyze the temporal dynamics of the variability of the average annual and maximum concentrations of pollutants in the runoff of the Oka River, we used long-term observational data on typical pollutants for the period 1984-2019. The assessment of the state of the quality of surface waters of the Oka River was carried out according to the values of the concentrations of pollutants in the upper, middle and lower reaches of the river. The dynamics of the main pollutants of the following indicators is considered: ammonium nitrogen, oil products, copper and zinc compounds and easily oxidized organic substances. It was found that in the upper reaches of the river (according to observations of the Oka – Orel city) the main pollutants are ammonium nitrogen and copper compounds, the average annual concentrations of which respectively increased to 9 values. A similar situation was observed downstream of the river (the Oka River – Kaluga city). As a result of the analysis, it was revealed that more noticeable changes in the concentration of pollutants are observed in the section of the river from the city of Murom to the city of Dzerzhinsk. Near the city of Murom, the content of oil products in the water sharply increases. From the beginning of the study period (1984) and until 1995, the average annual concentration varied from 5 to 30 values, and the maximum concentration in the year in creased to 87 values. After 2000, the content of oil products in water dropped sharply and the average annual value did not exceed 3 values, and the maximum concentration was 4-6 values. The paper analyzes the frequency of cases of exceeding the maximum permissible concentrations of pollutants in the Oka River in the mouth of the river. There was a high repeatability of the content of copper compounds in water, which varied from 70 to 88%. The frequency of cases of excess of easily oxidized organic matter in the mouth of the Oka River varied from 64 to 74%. Relatively low, although stable, the repeatability of the content of oil products in water remained, which ranged from 23 to 42%.

The «rainfall-runoff» system and its long-term fluctuations in the Siverskyi Donets River Basin (Ukraine)

2021 ◽  
Author(s):  
Hanna Bolbot ◽  
Vasyl Grebin
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
River Basin ◽  
Air Temperature ◽  
River Runoff ◽  
Annual Runoff ◽  
Annual Precipitation ◽  
Spring Flood ◽  
Current Period

<p>The current patterns estimation of the water regime under climate change is one of the most urgent tasks in Ukraine and the world. Such changes are determined by fluctuations in the main climatic characteristics - precipitation and air temperature, which are defined the value of evaporation. These parameters influence on the annual runoff distribution and long-term runoff fluctuations. In particular, the annual precipitation redistribution is reflected in the corresponding changes in the river runoff.<br>The assessment of the current state and nature of changes in precipitation and river runoff of the Siverskyi Donets River Basin was made by comparing the current period (1991-2018) with the period of the climatological normal (1961-1990).<br>In general, for this area, it was defined the close relationship between the amount of precipitation and the annual runoff. Against the background of insignificant (about 1%) increase of annual precipitation in recent decades, it was revealed their redistribution by seasons and separate months. There is a decrease in precipitation in the cold period (November-February). This causes (along with other factors) a decrease in the amount of snow and, accordingly, the spring flood runoff. There are frequent cases of unexpressed spring floods of the Siverskyi Donets River Basin. The runoff during March-April (the period of spring flood within the Ukrainian part of the basin) decreased by almost a third.<br>The increase of precipitation during May-June causes a corresponding (insignificant) increase in runoff in these months. The shift of the maximum monthly amount of precipitation from May (for the period 1961-1990) to June (in the current period) is observed.<br>There is a certain threat to water supply in the region due to the shift in the minimum monthly amount of precipitation in the warm period from October to August. Compared with October, there is a higher air temperature and, accordingly, higher evaporation in August, which reduces the runoff. Such a situation is solved by rational water resources management of the basin. The possibility of replenishing water resources in the basin through the transfer runoff from the Dnieper (Dnieper-Siverskyi Donets channel) and the annual runoff redistribution in the reservoir system causes some increase in the river runoff of summer months in recent decades. This is also contributed by the activities of the river basin management structures, which control the maintenance water users' of minimum ecological flow downstream the water intakes and hydraulic structures in the rivers of the basin.<br>Therefore, in the period of current climate change, the annual runoff distribution of the Siverskyi Donets River Basin has undergone significant changes, which is related to the annual precipitation redistribution and anthropogenic load on the basin.</p>

scholarly journals Long-term changes in central European river discharge for 1869–2016: impact of changing snow covers, reservoir constructions and an intensified hydrological cycle

2020 ◽  
Vol 24 (4) ◽  
pp. 1721-1740 ◽  
Author(s):  
Erwin Rottler ◽  
Till Francke ◽  
Gerd Bürger ◽  
Axel Bronstert
Keyword(s):  
Snow Cover ◽  
River Runoff ◽  
Hydrological Cycle ◽  
Flow Regimes ◽  
Time Frame ◽  
Long Term Effects ◽  
Mixed Flow ◽  
Discharge Data ◽  
Long Term Changes

Abstract. Recent climatic changes have the potential to severely alter river runoff, particularly in snow-dominated river basins. Effects of changing snow covers superimpose with changes in precipitation and anthropogenic modifications of the watershed and river network. In the attempt to identify and disentangle long-term effects of different mechanisms, we employ a set of analytical tools to extract long-term changes in river runoff at high resolution. We combine quantile sampling with moving average trend statistics and empirical mode decomposition and apply these tools to discharge data recorded along rivers with nival, pluvial and mixed flow regimes as well as temperature and precipitation data covering the time frame 1869–2016. With a focus on central Europe, we analyse the long-term impact of snow cover and precipitation changes along with their interaction with reservoir constructions. Our results show that runoff seasonality of snow-dominated rivers decreases. Runoff increases in winter and spring, while discharge decreases in summer and at the beginning of autumn. We attribute this redistribution of annual flow mainly to reservoir constructions in the Alpine ridge. During the course of the last century, large fractions of the Alpine rivers were dammed to produce hydropower. In recent decades, runoff changes induced by reservoir constructions seem to overlap with changes in snow cover. We suggest that Alpine signals propagate downstream and affect runoff far outside the Alpine area in river segments with mixed flow regimes. Furthermore, our results hint at more (intense) rainfall in recent decades. Detected increases in high discharge can be traced back to corresponding changes in precipitation.

Dynamic-stochastical modeling of long-term fluctuations in Lake Baykal levels and Angara River runoff

2017 ◽  
Vol 44 (3) ◽  
pp. 380-389 ◽  
Author(s):  
A. V. Frolov ◽  
T. Yu. Vyruchalkina
Keyword(s):  
River Runoff

Psychological Models of Suicide

2017 ◽  
Author(s):  
Shira Barzilay ◽  
Abbie Cohen
Keyword(s):  
Suicidal Behavior ◽  
Clinical Judgment ◽  
First Generation ◽  
Prognostic Models ◽  
Theoretical Approaches ◽  
Psychological Models ◽  
Demographic Risk ◽  
Demographic Risk Factors ◽  
And Behavior

A comprehensive model of suicidal processes and behavior is essential for the assessment of imminent risk for suicide and for the design of informed interventions. This chapter provides descriptions of the three generations of the most influential theories of suicidal behavior as well as an assessment of their strengths and limitations. First-generation models were based on clinicians’ individual experiences and, more recently, on consensus opinion and clinical judgment. Second-generation prognostic models hypothesized that suicide risk was determined by measurable long-term biological, clinical, or demographic risk factors. Third-generation models of suicidal behavior focused on dynamic risk elements, which appear later in life, change over time, and are operational immediately proximal to suicide. This chapter provides a historical perspective on the evolution of the theoretical approaches to the understanding of psychological processes that make suicide possible.

scholarly journals A Universal Law of Estuarine Mixing

2020 ◽  
Vol 50 (1) ◽  
pp. 81-93 ◽  
Author(s):  
Hans Burchard
Keyword(s):  
River Runoff ◽  
Numerical Test ◽  
Test Cases ◽  
Exchange Flow ◽  
One Dimensional ◽  
Estuarine Mixing ◽  
Flow Mixing ◽  
Universal Law ◽  
Total Exchange

AbstractA universal law of estuarine mixing is derived here, combining the approaches of salinity coordinates, Knudsen relations, total exchange flow, mixing definition as salinity variance loss, and the mixing–exchange flow relation. As a result, the long-term average mixing within an estuarine volume bounded by the isohaline of salinity S amounts to M(S) = S2Qr, where Qr is the average river runoff into the estuary. Consequently, the mixing per salinity class is m(S) = ∂SM(S) = 2SQr, which can also be expressed as the product of the isohaline volume and the mixing averaged over the isohaline. The major differences between the new mixing law and the recently developed mixing relation based on the Knudsen relations are threefold: (i) it does not depend on internal dynamics of the estuary determining inflow and outflow salinities (universality), (ii) it is exactly derived from conservation laws (accuracy), and (iii) it calculates mixing per salinity class (locality). The universal mixing law is demonstrated by means of analytical stationary and one-dimensional and two-dimensional numerical test cases. Some possible consequences for the salinity distribution in real estuaries are briefly discussed. Since the mixing per salinity class only depends on the river runoff and the chosen salinity, and not on local processes at the isohaline, low-mixing estuaries must have large isohaline volumes and vice versa.

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